1. Field of the Invention
The present invention relates to a display apparatus, in particular, to a display apparatus having a phase detection function and a phase detection method thereof.
2. Description of Related Art
Along with the incoming of the information era, the mass is no longer satisfied with presenting the data information in the form of texts or static pictures when receiving and transmitting data information. Instead, high-quality flat display apparatuses are used to exhibit fine dynamic images.
A conventional TV set is taken an example below, and when performing automatic phase detection on a received video graphics array (VGA) picture, the TV set performs calculations by using the characteristics of the VGA picture in the static state. FIG. 1 is a waveform chart of a part of a video signal of a VGA picture. The waveform in FIG. 1 represents an image with alternated black and white colours in the form of black, white, black, and white. It can be clearly seen from FIG. 1 that, in order to accurately capture the image information, the phase relation of the video signal must be detected accurately.
When the video information VO in the video signal of the VGA is sampled with a correct phase, the sampled pixels have great colour level differences. Therefore, the conventional automatic phase detection technique utilizes this feature, for example, various different phases are used to perform the sampling of the video information VO, so as to find out the phases that are capable of making the colour level differences STP1, STP2, STP3, and STP4 in the video signal become maximum, and the points STP1, STP2, STP3, and STP4 with the maximum colour levels are taken as the phases for all the video information, so as to sample the video information.
However, the images presented on the TV set are mostly dynamic, and seldom static. Therefore, the above conventional phase detection method cannot find out the obvious points with the maximum colour level differences to define the correct phases of all the video information. Therefore, the video information cannot be sampled correctly, which results in the distortion of displayed pictures.